Auto Repair Advice by Professional Automotive Experts
Car Noises
/ Chirping Noise
Why Does My Car Make a Chirping Noise?
Introduction - READ COMPLETELY BEFORE BEGINNING
When a chirping noise is detected first locate the area of the car it is being
generated from. If the noise is being generated while you drive and you are having
a hard time detecting the location of the chirping, have a helper ride along in
the rear seat to give a new perspective on the origin of the chirping noise. A chirping
noise can be generated by many things from a brake pad to a CAS (cam angle sensor).
It is common for a chirping noise to come and go depending on car conditions such
as hot or cold weather. Once the noise has been located follow the repair guide
below:
Chirping Noise
- Checking Brake Pad Wear: Many brake pads are equipped with
a "screamer" which indicates the brake pad has worn down to below minimum material
thickness. This noise indicator produces a chirping noise, either as the brakes
are applied or while the brakes are in idle position (not being used). A chirping
noise is produced as the wear sensor contacts the brake rotor in motion. If
this condition exists the noise will change as the brakes are depressed. If
the noise changes this sensor is in use and the brake pads need replacing.
Get the
Free Flash Player to see this video.
How to Change Front Brake Pads and Rotors
NOTE:
brake pads
and rotors that are
originally equipped on your car are manufactured with high quality metals and
brake lining material. There are many aftermarket manufacturers that create
sub standard brake components. These cheap brake parts can chirp, squeak, grumble
and wear out prematurely. Beware of brake components that have a "lifetime"
warranty. These parts are generally manufactured with inferior materials that
will delivery less performance and durability. Always insist on high quality
brake components, if you are unsure of the quality of brake parts available
use OEM (original equipment manufacturer) for best results.
- Checking Multi Rib/Serpentine Belt: The drive belt or multi
ribbed (serpentine) belt is an essential component of your vehicle. The primary
belt function is to supply power to the steering system, water pump, air pump
(if equipped) air conditioner and alternator. The belt is connected to the drive
pulley of the engine to supply power. This belt can produce a chirping sound
while the engine is running. This chipping will follow the engine RPM (engine
speed) and will be more noticeable at slow engine speeds. To check for the belt
condition, start with the engine off, look for belt glazing which is a shinning
condition inside the belt grooves.
Multi Ribbed Belt (cross view)
If glazing exits the belt must be replaced to fix the chirping sound. If
belt is cracked it could cause a chipping noise as the belt grips the pulleys
intermittently. Look for cracks in the belt "v" groves and replace as needed.
Cracked Multi Rib BeltFinally check the belt tension. If the belt
is loose it can cause the belt to produce a chirping noise due to the lack of
pressure needed for the belt to operate properly. The belt tensioner is responsible
for holding pressure on the belt using an idler pulley with a coil spring. Replacing
your car's multi rib belt or belt tensioner is relatively simple repair that
can be done in a few minutes with minor tools in most cases. Always wear protective
gloves and eyewear before you begin.
Drive Belt Tensioner (appearance will vary)
To replace the belt or the belt tensioner reference the "how to replace a
drive belt" video below:
Change Multi Rib Belt Video
-
Engine Chirping with the Multi Rib Belt Removed, (Ford Cars and Trucks
Only): Ford V6 and V8 engines only with a CAS (cam angle sensor). Starting
in the 90's ford started to manufacture engines equipped with a CAS. This sensor
assembly is basically a distributor housing with a sensor and trigger plate
mounted to a center shaft and is driven by the camshaft. The problem is, Ford
slowed the oiling to the distributor housing which causes the housing to seize
to the center shaft. The CAS seizes due to lack of oil making a high-pitched
chirping noise, like a loose belt. To check for this condition remove the drive
belt and restart the engine. If the noise is still there suspect the CAS, remove
the unit and (by hand) spin it. If the unit has failed it will be rough to turn,
either dissemble the unit to clean or replace the CAS housing with new. Be sure
to mark the position of the trigger plate/housing before removal, it MUST go
back in the same position or drivability problems will follow.
- Checking Accessory Bearings:
A bearing is designed to provide rolling
support to a shaft of any kind such as: alternator, starter, water pump, power
steering, air conditioner, air pump etc. If a chirping noise is being produced
after you have checked the drive belt a bearing could be going out. To check
for this condition remove the drive belt and rotate each accessory to make sure
there is no grinding or rough spots in the operation.
Expanded Bearing View
If grinding or rough spots occur replace
the accessory in question. Sometimes you can disassemble the unit and replace
the failed bearing with a new unit and reassemble, but in accessories like a
water pump the bearings are not serviceable.
Accessory Bearing
- Axle Bearing Failure: An axle bearing is designed to support the
weight of the vehicle by allowing the wheels to rotate. These bearings are manufactured
with high grade steel that resists wear under extreme conditions. When an axle
bearing fails it allows metal to contact metal under pressure with a linear
motion creating a chirping noise. Remove axle bearing and replace with new and
recheck. Some vehicles are equipped with a bearing hub assembly. This style
of bearing is replaced by un-bolting the bearing hub assembly and replacing
it with new.
Axle Bearing Hub
-
Drive Shaft U Joints. A driveshaft U joint is designed to act as a
rotating junction that can be flexible while still transferring energy from
the engine to the
rear differential. A universal joint or U joint is constructed of 4 bearing
caps that house multiple needle bearings. The universal joint is lubricated
by adding grease through a zirk fitting on the joint. Some u joints are manufactured
with a proper amount of grease and do not need service and therefore do not
have a service fitting. If a universal joint fails it can make a chirping noise
that contours the motion of the car. This condition is most noticeable at very
slow speeds, and fades at higher speeds. To check for this condition inspect
the U joint and look for a light rust powder around the bearing cups. This rust
colored powder is caused by metal disintegrating and is a sign of universal
joint failure. When a universal joint has failed it must be replaced and cannot
be repaired.
Universal or "U" Joint
-
Checking Clutch Noise: When your car is stopped or coming
to a stop the engine needs to be disconnected from the transmission or the engine
will stall. With
automatic transmission vehicles a
torque converter is used to separate the two units, but with
manual transmission vehicles a clutch assembly is used to do the job. This
clutch kit or unit is composed of a clutch disc, pressure plate, throw out and
pilot bearings. (Some front wheel drive vehicles do not use a pilot bearing).
Both types of vehicles use a flywheel but are designed a little differently.
An automatic transmission has a lighter weight unit that the torque converter
bolts directly to and is sometimes referred to as a flex plate. A manual transmission
flywheel assembly is made heavier to help engine inertia and to make shifting
smoother. The clutch pressure place bolts to the flywheel trapping the clutch
disc in-between. The throw out bearing presses against the pressure plate to
engage and release the disc. The pilot bearing is mounted in the flywheel and
holds the input shaft for the transmission steady. When a throw out bearing
starts to fail it can make a chirping noise that is audible when the clutch
pedal is pressed or released. If the chirping noise stops or starts suspect
this bearing.
Clutch and Flywheel Assembly (Cut Away)
Click for more:
Engine Chirping Sounds
For manufacturer specific procedures for any of the steps above please visit
our car repair
manual page.
Car Noises /
Chirping Noise
Check Manufacturer Specific Chirping
Noise Questions and Answers
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